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by jahboater
Thu Nov 14, 2019 5:40 pm
Forum: General discussion
Topic: Proper shutdown
Replies: 18
Views: 261

Re: Proper shutdown

But when the board powers up, it recognizes an improper shutdown and tries to close/fix files improperly left open. Windows knows when the CPU has lost power, I guess Linux knows it as well. Yes, it does. A flag is set when when the system is shutdown cleanly. When the system boots and the flag is ...
by jahboater
Wed Nov 13, 2019 8:17 am
Forum: Compute Module
Topic: eMMC over SD, or SSD
Replies: 7
Views: 153

Re: eMMC over SD, or SSD

tomsimmons wrote:
Wed Nov 13, 2019 7:34 am
I note that the Compute modules come with eMMC, well most do. What is longevity of the eMMC compared with a class 10 domestic SD?
The eMMC storage is on-board, so whatever its longevity is, you likely have to replace the module when it fails.
by jahboater
Tue Nov 12, 2019 1:49 pm
Forum: Beginners
Topic: overclocking on boot only
Replies: 5
Views: 107

Re: overclocking on boot only

i need about 8 sec to have my program starting My Pi4 (Raspbian Lite) starts in ... $ systemd-analyze Startup finished in 1.356s (kernel) + 13.991s (userspace) = 15.347s graphical.target reached after 13.953s in userspace $ If you want to optimize it further, look at the output from the "blame" and...
by jahboater
Tue Nov 12, 2019 12:59 pm
Forum: Beginners
Topic: overclocking on boot only
Replies: 5
Views: 107

Re: overclocking on boot only

Try:

Code: Select all

initial_turbo=30
This runs it in turbo mode for the first 30 seconds.

I assume you are running Raspbian Lite which boots quickly anyway.

You may be interested in these systemd commands:

Code: Select all

systemd-analyze

Code: Select all

systemd-analyze blame

Code: Select all

systemd-analyze critical-chain
by jahboater
Mon Nov 11, 2019 10:08 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

John_Spikowski, Strictly speaking there are no associative arrays in ScriptBasic... Who are you quoting there? Now you have to explain something because the message I always got before is that ScriptBasic arrays are not any kind of normal array in linearly addressable memory. But rather associative...
by jahboater
Mon Nov 11, 2019 9:07 am
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

Gavinmc42 wrote:
Mon Nov 11, 2019 9:00 am
150K is a bit arbitrary, was that your only requirement?
If the 150K refers to the install image size of the interpreter, then effectively Python is zero because no image is needed - it is already included in Raspbian.
by jahboater
Sun Nov 10, 2019 10:51 pm
Forum: General discussion
Topic: What is the maximum temperature of the CPU before it gets demaged ?
Replies: 14
Views: 649

Re: What is the maximum temperature of the CPU before it gets demaged ?

HermannSW, Can you try it not overclocked? Yes. It didn't seem to make any (easily) measurable difference. But 100MHz is a small, safe, overclock for the Pi4. Since I don't have fans, your and my measurements should match somehow. Perhaps your overclocking reduced heat (should not), or you did not p...
by jahboater
Sat Nov 09, 2019 5:26 pm
Forum: Python
Topic: Conversion
Replies: 17
Views: 357

Re: Conversion

You should use python3 integer division. def convert_long_to_bytes(i): i %= 4294967296 n4 = i % 256 i //= 256 n3 = i % 256 i //= 256 return (i // 256, i % 256, n3, n4) I'm pretty sure its vastly more efficient, and simpler, than converting it all to floating-point, then rounding it, and finally trun...
by jahboater
Sat Nov 09, 2019 3:23 pm
Forum: General discussion
Topic: Board rev for USB-C fix?
Replies: 33
Views: 1508

Re: Board rev for USB-C fix?

swdrumm wrote:
Sat Nov 09, 2019 3:20 pm
I have several USB-C PD chargers for other devices.
Many of those likely wont work anyway for reasons that have been published here many times already.
You need a PSU not a charger.
by jahboater
Sat Nov 09, 2019 3:19 pm
Forum: General discussion
Topic: Board rev for USB-C fix?
Replies: 33
Views: 1508

Re: Board rev for USB-C fix?

We are not buying a board with a design flaw when a new one is coming. It is that simple. Please do not start with the issue being minor, etc etc. You will likely not be buying any boards then, there are always revisions for most PCB's. Why not just use the official PSU? its cheap and you can be su...
by jahboater
Sat Nov 09, 2019 1:04 pm
Forum: General discussion
Topic: What is the maximum temperature of the CPU before it gets demaged ?
Replies: 14
Views: 649

Re: What is the maximum temperature of the CPU before it gets demaged ?

The in-built throttling means you can't practically run over 85°C without using mythical overclocking settings that would be outside the spec for the processor. With the latest firmware, there seems to be no risk of even reaching 85C now. My Pi4 has no fan , and the maximum temp is about 72C when r...
by jahboater
Sat Nov 09, 2019 7:31 am
Forum: Python
Topic: Conversion
Replies: 17
Views: 357

Re: Conversion

You may need // instead of / for integer division.
by jahboater
Fri Nov 08, 2019 1:45 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

ejolson wrote:
Fri Nov 08, 2019 11:14 am
John_Spikowski wrote:
Fri Nov 08, 2019 5:34 am

Code: Select all

jrs@jrs-laptop:~/sb/tatami$ scriba Tatami.sb
The smallest room size s for which T(s) = 100 is 240240
jrs@jrs-laptop:~/sb/tatami$ 
Is the correct answer for T(s)=100 produced by the original C code?
The original C code says:

Code: Select all

The smallest room size s for which T(s) = 100 is 6683040
by jahboater
Fri Nov 08, 2019 3:02 am
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

From everything I ever heard about it I got the impression it was some mythic beast of software development that was slain before it could get off the ground. It truly is a mythic beast with a lot of interesting ideas. I personally applaud the choice of PL/I as the system programming language. You ...
by jahboater
Thu Nov 07, 2019 8:00 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

Looking at the disassembled code, I see that the Pi4 does software integer division! Does the Pi4 not support the IDIV instruction? Yes the Pi4 has SDIV and UDIV instructions (Signed and Unsigned division), but sadly in 32-bit mode (Raspbian) they only work for 32-bits, and 64-bit division is done ...
by jahboater
Thu Nov 07, 2019 2:24 pm
Forum: Python
Topic: Get pi CPU temp and load
Replies: 15
Views: 1833

Re: Get pi CPU temp and load

Sorry for the bump I still can't find an answer for this , how to get the CPU Load. and it can't be that hard - becuase you can see it in the menu as "CPU Usage Monitor", so the number and calculation is there. so it must be a way to reach and get it , no? uptime and top give you the "load averages...
by jahboater
Thu Nov 07, 2019 1:38 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

As far as I understand PL/1 was not chosen to implement Multics. Rather it was defined in order to do so. Resulting in the situation that they had defined and written an operating system but had no compiler to build it with! I thought PL/1 was developed by IBM ? The Multics system I used was by Hon...
by jahboater
Thu Nov 07, 2019 1:35 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

Heater wrote:
Thu Nov 07, 2019 8:33 am
Wow, what. You mean Multics actually became an operating system that one could actually run?
Yes, it was production OS. I used it briefly!

What stood out for me was the single level of storage.
Memory and disk were indistinguishable.

Been done since of course by IBM and Intel.
by jahboater
Thu Nov 07, 2019 1:22 pm
Forum: General discussion
Topic: Interesting interview with Eben in Physics World
Replies: 41
Views: 1463

Re: Interesting interview with Eben in Physics World

@jahboater, Isn't that true of any of type computer system disk? Its not SD card specific (its an OS problem). Yes of course. Except I would say it's not an OS problem. Perhaps an OS configuration problem. Yes, its not a problem as such, its just that any modern large OS will have a disk cache whic...
by jahboater
Thu Nov 07, 2019 11:39 am
Forum: General discussion
Topic: Interesting interview with Eben in Physics World
Replies: 41
Views: 1463

Re: Interesting interview with Eben in Physics World

File systems do get corrupted on random power down. Isn't that true of any of type computer system disk? Its not SD card specific (its an OS problem). The only difference perhaps is that SD cards are tiny and cheap, so maybe people don't take as much care of them as they did for expensive large spi...
by jahboater
Thu Nov 07, 2019 10:06 am
Forum: General discussion
Topic: Interesting interview with Eben in Physics World
Replies: 41
Views: 1463

Re: Interesting interview with Eben in Physics World

The SD card solution is just too unreliable for 24/7 running... Really? All my Pi's run 24/7 and have done for years. Never a problem, and SD card corruptions simply don't happen. User error, or unreliable power source. Compared to most PC's, the electric bill for the ARM powered Pi is tiny, so its...
by jahboater
Wed Nov 06, 2019 1:08 pm
Forum: General discussion
Topic: Trouble Downloading
Replies: 6
Views: 190

Re: Trouble Downloading

I tried a download of the largest image (full Raspbian with all the suggested software) and arrived in around 15 minutes on my slow connection.
by jahboater
Wed Nov 06, 2019 8:32 am
Forum: General discussion
Topic: Buster : downgraded 'rm' command , how to upgrade
Replies: 4
Views: 174

Re: Buster : downgraded 'rm' command , how to upgrade

Heater wrote:
Wed Nov 06, 2019 5:38 am
Oddly I now notice there is bot a -r and -R option. Which do the same recursive thing.
That's for historical reasons. There were some versions of rm on UNIX that needed -R.
by jahboater
Mon Nov 04, 2019 10:58 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

ejolson wrote:
Mon Nov 04, 2019 8:42 pm
Although operations with zero-terminated strings are difficult to vectorise.
Intel SSE4.2 introduced some instructions for vectorised zero terminated string operations (among other things).
by jahboater
Mon Nov 04, 2019 9:08 pm
Forum: General programming discussion
Topic: Liberation through Computer Literacy
Replies: 1577
Views: 79407

Re: Liberation through Computer Literacy

True, but you need to scan it from beginning to end each time you want to determine its length. Doesn't matter in practice (when have you ever found it to be a major overhead in a real program?). And Intel CPU's have hardware instructions just for the purpose which are very quick. You trade off the...

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